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Explain the acid-base indicator constant?

Important Questions on Acids, Bases and Salts

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Why does a pink colour appear upon gradually adding sodium hydroxide to a solution of acid having 2-3 drops of phenolphthalein?
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An acid-base indicator(pKa = 4.5271)has the acid form red and basic form blue. If we need 75% red to be converted into 75% blue form in solution, the change in pH of solution should be :
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What is pH of 1 M acetic acid solution? If volume one litre solution be diluted  to X×104 L  so that pH of resulting solution is twice the original value (Ka = 1.8 x 10- 5 ). Find the value of X.
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You are given the dilute sulphuric acid. What is effect of it on the phenolphthalein?
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 Which of the following indicators is used in the activity?

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Following is the titration curve of CH3COOH against NaOH added with phenolphthalein as the indicator.

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KIn value of phenolphthalein is 4.0 x 10-10. Thus, incorrect statement is
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An acid-base indicator has a  Ka of 3.0×10-5. If the acid form of the indicator is red and the basic form is blue, then
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What will you observe when a drop of phenolphthalein is added to the solution of lime water.
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Name any two human-made indicators.
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When KMnO4 solution is titrated with a solution containing Fe2+ ion, the indicator used in this titration is
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What is the colour of this indicator in (a) Neutral (b) Acidic (c) Basic solution?
Phenolphthalein 
 
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What is substance 'Y'?

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An indicator, HIn has a standard ionization constant of 9 · 0 × 1 0 - 9 . The acid colour of the indicator is yellow, and the alkaline colour is red. The yellow colour is visible when the ratio of yellow form to red form is 30:1 and the red colour is predominant when the ratio of red form to yellow form 2 : 1. What is the pH range of the indicator? ​Hence, report ∆pH the difference in term pH values of the range.
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Write the quadrants in which the following points lie:

-4,7

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An indicator has a pKa of 7.5. What is the ratio of the concentration of the base form to the concentration of the acid form ([A- ]/ [HA], in a buffer solution in which the pH is 6.5 ?
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4-methyl benzene sulphonic acid reacts with sodium acetate to give
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Cotyledons are also called-
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An element E reacts with water to form a solution which turns phenolphthalein solution pink. The element E is most likely to be:

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An acid-base indicator has Ka = 3.0×10-5. The acid form of the indicator is red and the basic form is blue. Then:
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What is substance 'X'?

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